Are those Muslim women who wear a burqa in any way better Muslims than those Muslim women who only wear a hijab?

nope. who am I to judge ? I've never heard an islamic scholar saying that a hijabi is better than a non hijabi . Who knows if this non hijabi is beloved to Almighty еще than a hijabi . Ислам teaches us to cover ourselves yet it never force us to do anything that we don't want to :)